1. Field
The presently disclosed subject matter relates to a reflector for a vehicle and, more particularly, to a reflector for a vehicle which allows increasing the luminous intensity at a measurement point for obtaining the luminous intensity in the direction of an observation angle.
2. Description of the Related Art
In the field of vehicle reflectors, it has been desired to increase the luminous intensity in the direction of an observation angle. In order to increase the luminous intensity in the direction of an observation angle, for example, the reflector for vehicle described in Japanese Patent No. 3340640 has been proposed.
As illustrated in FIGS. 14 and 15, the reflector for a vehicle described in Japanese Patent No. 3340640 includes a plurality of retroreflective elements 211 configured to retroreflect incident light, which becomes incident parallel to a horizontally arranged reference axis AX, in a direction inclined at a prescribed angle to the reference axis AX. The retroreflective element 211 includes a first reflection surface 1, a second reflection surface 2 and a third reflection surface 3 which are arranged in an adjoining relation so as to form corners of a substantial cube (see FIG. 15). Each of the reflection surfaces 1 to 3 is inclined at the same angle (approximately 35° 17′) to the reference axis AX which is horizontally arranged (see FIG. 14), and each of the second reflection surface 2 and the third reflection surface 3 is formed in positions reached after the second reflection surface 2 and the third reflection surface 3 are each rotated through the same angle (±120° 6′) around the reference axis AX as center (see FIG. 15).
In the reflector for a vehicle 210 according to the above-described configuration, the incident light which becomes incident parallel to the reference axis AX, reflects obliquely upward at a prescribed angle to the reference axis AX due to the action of a retroreflective element (the first to third reflection surfaces 1 to 3). As illustrated in FIG. 16, focusing points P2 and P3 on both sides approach the topmost focusing point P1. Therefore, it becomes possible to increase the luminous intensity at measurement points for obtaining luminous intensity in the direction of an observation angle.